Pyrolysis of brominated feedstock plastic in a fluidised bed reactor

Fire retarded high impact polystyrene has been pyrolysed using a fluidised bed reactor with a sand bed. The yield and composition of the products have been investigated in relation to fluidised bed temperature. The bromine distribution between the products and a detailed analysis of the oils using GC-FID/ECD, GC-MS, FT-ir, and size exclusion chromatography has been carried out. It was found that the majority of the bromine transfers to the pyrolysis oil and the antimony was detected in both the oil and the char. Oil made up over 89.9% of the pyrolysis products. Over 30% of the oil consisted of benzene, toluene, ethylbenzene, styrene and cumene. The pyrolysis gases were mainly hydrocarbons in the C1-C4 range but some HBr and Br2 was detected

Classification of Minimal Separating Sets in Low Genus Surfaces

Consider a surface $S$ and let $M\subset S$. If $S\setminus M$ is not connected, then we say $M$ \emph{separates} $S$, and we refer to $M$ as a \emph{separating set} of $S$. If $M$ separates $S$, and no proper subset of $M$ separates $S$, then we say $M$ is a \emph{minimal separating set} of $S$. In this paper we use methods of computational combinatorial topology to classify the minimal separating sets of the orientable surfaces of genus $g=2$ and $g=3$. The classification for genus 0 and 1 was done in earlier work, using methods of algebraic topology.Comment: 24 pages, 5 figures, 2 tables (11 pages

The adjustment of barotropic currents at the shelf break to a sharp bend in the shelf topography

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1996During January-March, Scotian Shelf water has been observed to flow episodically from the southwestern Scotian Shelf directly across the Northeast Channel to Georges Bank. The possible factors that allow Scotian Shelf water to break the topographic constraint presented by the Northeast Channel and flow directly to Georges Bank are considered. As a simple analog to the flow over the southwestern Scotian Shelf near the Northeast Channel, the adjustment of a barotropic current near a shelf-break to a sharp bend in the shelf topography is studied numerically. For parameters within the oceanographic range, the adjustment to the bend is smooth and steady with no eddies shed at the corner. The vorticity dynamics allow a balance between the vortex stretching in the flow and the curvature in the flow. This is possible since the bend is a right-hand one facing downstream, a similar balance not being possible for a left-hand bend, in which case eddy formation is likely. A simple model of this balance clarifies the vorticity dynamics and provides the scaling rc = √eL/0.765 for any streamline in the flow, where rc is the radius of curvature at the corner, E = u0/fL and L = h0/b, where uo is the initial speed, f the coriolis parameter, h0 the initial depth and b the bottom slope. These results show that other factors such as stratification, wind stress, and time-dependent inflow must play a role in any flow across the Northeast Channel.I am very grateful to the US-GLOBEC program for providing the funding for this study (N.S.F. grant OCE-9313671)

Merged ionization/dissociation fronts in planetary nebulae

The hydrogen ionization and dissociation front around an ultraviolet radiation source should merge when the ratio of ionizing photon flux to gas density is sufficiently low and the spectrum is sufficiently hard. This regime is particularly relevant to the molecular knots that are commonly found in evolved planetary nebulae, such as the Helix Nebula, where traditional models of photodissociation regions have proved unable to explain the high observed luminosity in H_2 lines. In this paper we present results for the structure and steady-state dynamics of such advection-dominated merged fronts, calculated using the Cloudy plasma/molecular physics code. We find that the principal destruction processes for H_2 are photoionization by extreme ultraviolet radiation and charge exchange reactions with protons, both of which form H_2^+, which rapidly combines with free electrons to undergo dissociative recombination. Advection moves the dissociation front to lower column densities than in the static case, which vastly increases the heating in the partially molecular gas due to photoionization of He^0, H_2, and H^0. This causes a significant fraction of the incident bolometric flux to be re-radiated as thermally excited infrared H_2 lines, with the lower excitation pure rotational lines arising in 1000 K gas and higher excitation H_2 lines arising in 2000 K gas, as is required to explain the H_2 spectrum of the Helix cometary knots.Comment: 4 pages, accepted by ApJL, scheduled December 20 issu

2014 Fed Challenge Script: Current State of the Economy

Good afternoon everyone and thank you for having us here today. Though the recession began in 2007 and officially ended in 2009, recovery has been painfully slow. GDP growth has been insufficient to close the output gap, there continues to be slack in the labor market and inflation has stabilized below the Federal Reserve percent target. We are not meeting our dual mandate of full employment and stable prices even 6 years after the end of the recession. Despite some signs of strengthening in the economy during the past year, we do not believe that economy is on a self-sustaining path of recovery. Furthermore, the monetary policy actions taken by the Fed thus far to pull us out of the Great Recession have been insufficient. We propose a substantial strengthening of the our forward guidance; specifically, a commitment not to raise the federal funds rate until nominal GDP has returned to a path that we consider consistent with the dual mandate. [excerpt